1. Field of the Invention
The invention relates to a coupling arrangement for spray-tube in washing machines or the like in which a ring packing on the end of a spray-tube is pressed into a coupling opening of the machine by a clamping device engaging the spray-tube.
2. Description of the Prior Art
In the case of machines for washing dishes, glass vessels, laboratory devices, etc., it is known to be of advantage if at least the spray tubes that are supplied with undistilled water can be removed for the purpose of cleaning them and they are thus known to be provided for such a purpose with rapidly detachable spray-tube couplings. In the case of a known spray-tube coupling of the type described (German Utility Model 6,941,340), the spray tubes are inserted into coupling openings formed laterally on a coupling block. Each spray tube is provided with a ring packing on an end to be coupled. During the insertion of the spray tube into the coupling opening the packing contacts the preferably conically formed boundary of the coupling opening and is stressed. Horizontal side bars extend from the coupling block and are provided with recesses that are engaged by pins attached to the corresponding spray tube. The recesses are shaped in such a manner that during the insertion of the pins, the spray tube is initially pushed to an increasing extent into the coupling opening with th ring packing being subjected to a strong stress. Subsequently as the pins are inserted further into the recesses, the spray tube is backed away somewhat from the coupling opening, with the pins locking into the recesses as a result of the pressure of the ring packing, so that finally the spray tube is held firmly in the coupling opening due to the pressure or stress on the ring packing. Side bar elements are additonally provided with safety stirrups with which the pins can be locked in the recesses.
After a certain period of operation, sealing problems may result in connection with such known spray-tube couplings. In particular, it is known that after a removal of the spray tubes, e.g., for the purpose of cleaning them, the ring packings must be replaced, since they lose their elasticity and cannot be used again due to the high stressing through the washing liquids and the high temperatures.